Automatic release hand brake control system

ABSTRACT

In a rail vehicle hand brake having a release activated by a pneumatic cylinder, the present control system includes a manual valve having an output connected to a source of pressure at an input when manually activated. A volume is to be charged by the source of pressure. A choke connects the volume to exhaust. The volume and the choke prolong the time the source of pressure is connected to the pneumatic cylinder after the manual valve is activated.

BACKGROUND AND SUMMARY

The present disclosure relates generally to automatic hand brakes andmore specifically to an automatic release of hand brakes control system.

Hand or parking brakes on rail vehicles generally include a chainconnected to the vehicle brakes and wound around a wheel. The brakes areapplied by rotating the wheel and tensioning the chain. The hand brakeincludes a trigger or lever which, when activated, automaticallyreleases the tension on the chain and releases the parking hand brake.To make sure the hand brake is fully released, the release mechanism hasa prolonged release mechanical structure.

Two cylinders may be provided on the hand brake to apply the brakes byturning the wheel to tension the chain and a second cylinder to releasethe brakes by interacting with the release trigger or lever. A pneumaticsystem to control the two cylinders and the use of parallel manuallyactuated valves and electro-pneumatic valves are illustrated in U.S.Pat. No. 6,394,559 and U.S. Pat. No. 7,014,275, for example. The applyand release cylinders are activated by the manual valves as long as themanual valves are activated to connect a source of pressure to thecylinder and for a short period there after determined by the choke onthe exhaust port of the manual valve.

The actuation of the electro-pneumatic valves as discussed herein may beby an electrically controlled pneumatic (ECP) brake network and throughthe cars control unit (CCU). The overall control system is described,for example, in U.S. Pat. No. 7,073,753. Remote control of the handbrake by hand-held terminal is described in U.S. Pat. No. 6,175,784.

In a rail vehicle hand brake having a release activated by a pneumaticcylinder, the present control system includes a manual valve having anoutput connected to a source of pressure at an input when manuallyactivated. A volume is to be charged by the source of pressure. A firstchoke connects the volume to exhaust. A first pneumatic valve has apilot port connected to the volume and has an output connected to thesource of pressure at an input when the volume is charged to apredetermined pressure to activate the first pneumatic valve and afterthe manual vale is activated. The output of the first pneumatic valve isconnected to the pneumatic cylinder. The volume and the first chokeprolong the time the source of pressure is connected to the pneumaticcylinder after the manual valve is activated.

The volume may be connected to the output of the manual valve andcharged by the source of pressure when the manual valve is activated.Alternatively, the volume may be selectively connected to either thesource of pressure or the pilot port of the first pneumatic valve by asecond pneumatic valve. The second pneumatic valve connects the volumeto the source of pressure when deactivated and to the pilot port of thefirst pneumatic valve when activated. A pilot port of the secondpneumatic valve is connected to the output of the first pneumatic valveand activated when the first pneumatic valve is activated.

The output of the manual valve is connected to the pilot port of thefirst pneumatic valve for initially activating the first pneumaticvalve. The manual valve may be a rocker valve.

A manifold includes passages for interconnecting and in which is mountedthe manual valve, the first pneumatic valve and the first choke. Themanifold includes ports for the source of pressure and the pneumaticcylinder. The volume is in the manifold.

Also, the control system may include a manual valve having an outputconnected to a source of pressure at an input when manually activatedand a volume connected to the output of the manual valve and charged bythe source of pressure when the manual valve is activated. A chokeconnects the volume to a source of lower pressure when the volume ischarged. The volume and the choke prolong the time the source ofpressure is connected to the pneumatic cylinder after the manual valveis activated.

The volume may be connected to the cylinder. Alternatively, the systemmay include a pneumatic valve having a pilot port connected to thevolume and having an output connected to the source of pressure at aninput when the volume is charged to a predetermined pressure to activatethe pneumatic valve and after the manual valve is activated. The outputof the first pneumatic vale is connected to the cylinder.

The system may include an actuator having a piston operatively connectedto the manual valve. The volume is in the actuator on a first face ofthe piston for holding the piston and the manual valve actuated for theprolonged time. The choke continuously connects the volume to a secondface of the piston opposite the first face of the piston and may be apassage in the piston. The manual valve is a slide valve having a slideand the piston is the slide of the slide valve. A detent holds themanual valve in the activated position for the prolonged time.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a hand brake control system for a rail vehiclehand brake according to a first embodiment of the present disclosure.

FIG. 2 is a schematic of a hand brake control system for a rail vehiclehand brake according to a second embodiment of the present disclosure.

FIGS. 3A and 3B are cross-sectional views of a manifold includingportions of the schematic of FIG. 1 according to the present system.

FIG. 4 is a schematic of a hand brake control system for a rail vehiclehand brake according to a third embodiment of the present disclosure.

FIGS. 5A, 5B, and 5C are cross-sectional views of a manifold includingportions of the schematic of FIG. 1 at three stages according to thepresent system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of a control system for automatic release of a handbrake is illustrated in FIG. 1. A pneumatic cylinder 10 via a clevis, ora similar mechanism, like a pushrod with a ball-end, and a correspondingsocket geometry on the release lever or a cable 11 as shown in FIG. 4,is connected to the trigger or the release lever of the hand brake on avehicle. A pneumatic control circuitry 12 includes a first source ofpressure shown as a reservoir 14 and a restriction or choke 16. A secondchoke 18 connects the cylinder 10 to exhaust or atmosphere. Any systemleaking is allowed to go to exhaust through choke 18 and thus preventsundesired release of the hand brake.

The reservoir 14 may be an emergency reservoir portion or an auxiliaryreservoir portion generally available on the vehicle. This is just anexample of a reservoir. A port or quick disconnect fitting may beprovided to allow an external source of pressure not on the vehicle tobe connected to the circuit 12. This may be, for example, from away-side air supply and offers an alternative to the reservoir if thereservoir does not have sufficient pressure to operate the system.

A manual valve 30 in combination with a volume 20 control a firstpneumatic valve 40 to selective connect the source of pressure 14 to thecylinder 10. The volume 20 and a choke 22 prolong the time the source ofpressurize 14 is connected to the pneumatic cylinder 10 by pneumaticvalve 40 after the manual valve 30 is activated. This prolongsactivation of the release mechanism of the hand brake to assure fullrelease of the hand brake.

The source of pressure 14 is connected to a first input 32 of a firstvalve 30. The first valve 30 is illustrated as a manually operated valvehaving an operator 34. The output 36 of valve 30 is connected to thevolume 20. Spring 38 biases the valve 30 in the shown position where thesupply pressure at input 32 is not connected to the output 36. Thevolume 20 is charged when, valve 30 is activated and maintains itscharge after the valve 30 is released or deactivated for a preselectedperiod determined by the choke 22. Preferably, this prolonged period isin the range of 5 to 10 seconds. Although the choke 22 is shownconnected to exhaust or atmosphere in FIGS. 1 and 2, it can be connectedto any source or volume of lower pressure than that of the chargedvolume 20 as shown in FIG. 4.

The manual operator 34 of the valve 30, as shown in FIG. 3A, may be arocker type mechanical lifter that can be actuated from any 360 degreesabout its center. The rocker mechanism also provides for automatic resetof the valve 30 when the mechanical actuator is released andautomatically returns to its neutral position.

A second valve 40 is a pneumatic valve having an input 42 connected tothe source of pressure 14 and an output 46 connected to the cylinder 10.A pilot port 44 of valve 40 is connected to the volume 20. Spring 48biases the valve 40 in the shown position where the supply pressure atinput 42 is not connected to the output 46. The valve 40 is moved to aposition connecting the source of pressure at its input 42 to its output46 and the cylinder 10 when the volume is charged to a predeterminedtrip pressure. It is held in this position until the volume is reducedbelow the trip pressure by choke 22. The manual valve 30 only has to beactivated for ½ to 1 seconds for the volume to reach the trip pressureand in the range of ½ to 1 seconds to reach a pressure which willmaintain valve 40 activated for 5 to 10 seconds.

A third valve 50 may be provided as illustrated as an electro-pneumaticvalve. The first input 52 is connected to the pressurized source 14. Asecond input 54 is connected to exhaust or atmosphere. The output 56 isconnected to the cylinder 19 via a one way check valve 59. Spring 58biases the valve 50 in the position shown, wherein the connection to thesupply at input 52 is terminated and exhaust at input 54 is connected toits output 56 and input of cylinder 10. Thus, in the stable positionshown of the valves 30, 40 and 50, the release cylinder 10 isdeactivated.

For manual actuation using operator 34, the valve 30 is moved to itsapplied or activated position connecting the pressurized supply at input32 to its output 36 and charging volume 20. Once charged to a trippingpressure, the pressure in volume 20 moves valve 40 to its activatedposition connecting the pressurized supply at input 42 to its output 46and to the cylinder 10. This activates cylinder 10, activating therelease trigger and releasing the hand brake. Once the operator releasesthe operator 34, the spring 38 causes the valve 30 to move to its stableposition, cutting off the supply of air to the volume 20 which prolongsthe activation of valve 40 until its pressure is reduced by choke 22 tobelow the trip pressure of the valve 40. Once the valve 40 returns toits stable position, the source of pressure 14 is cut off and cylinder10 is deactivated by bleeding of the activation pressure by choke 18.

The electro-pneumatic valve 50 may be actuated by an electric signalfrom its stable position shown to a second position. This connects thepressurized supply at input 52 to its output 56. This is provideddirectly through input 34 to output 36 of valve 30. This activates thecylinder 10 which moves the brake release trigger or lever. Upon removalof the signal, spring 58 moves the valve 50 back to the position shown,connecting the cylinder 10 to exhaust and input 54 of valve 50.

The valve 50 may be connected to an ECP car control device CCD which isconnected to a train line and activated upon receiving a hand brakerelease signal from the locomotive. Providing such system is describedin U.S. Pat. No. 7,073,753 and is incorporated herein by reference.Alternatively, the valve 50 may be actuated by a hand held devicecarried by operator as he walks the train. Such a device is shown, forexample, in U.S. Pat. No. 6,175,784.

A second embodiment of a control system for automatic release of a handbrake is illustrated in FIG. 2. As in the first embodiment, the sourceof pressure 14 is connected to the first input 32 of a first valve 30.Spring 38 biases the valve 30 in the shown position where the supplypressure at input 32 is not connected to the output 36. In thisembodiment, the output 36 of valve 30 is connected directly to the pilotport 44 of the first pneumatic valve 40.

The volume 20 is selectively charged from the source of pressure 14 orconnected to the pilot port of the first pneumatic valve 40 by a secondpneumatic valve 60. Port 66 of valve 60 is selectively connected toports 62 for the source of pressure 14 or port 64 connected to pilotport 44 of valve 40. Spring 68 biases the valve 60 in the shown positionwhere the supply pressure 14 at input 62 is connected to the output 66to charge the volume 20. A pilot port 61 of the valve 60 is connected tothe output 46 of valve 40.

Once valve 40 is activated by the manual valve 30, the pressure at itsoutput 46 activates the cylinder and the valve 60. The valve 60 thenmoves to disconnect the source of pressure 14 from the volume 20 andconnect the volume 20 to the pilot port 44 of the valve 40. As in thefirst embodiment, volume 20 will prolong the activation of valve 40after the release of manual valve 30 as determined by the choke 22.

An efficient implementation of portion of the circuitry 12 of FIG. 1 isshown in FIGS. 3A and 3B. A manifold 70 includes a body 72 with faceplates 74 and 76. The manifold 70 includes passages for interconnectingand in which is mounted the manual valve 30, the first pneumatic valve40, the volume 20 and the first choke 22. The manifold includes portsfor the source of pressure 14 and the pneumatic cylinder 10.

The manual valve 30 is mounted in bore 71 and the pneumatic valve 40 ismounted in bore 73. A passage 75 connects the output 36 of the manualvalve to the volume 20 in bore 73 below the piston/actuator 41 of valve40. This is also the pilot port 44 for the valve 40. The portion of thebore 73 above the piston is connected to atmosphere directly, while thevolume 20 below the piston 41 is connected to atmosphere or exhaust bychoke 22 as shown in FIG. 3B. A passage 77 connects the source ofpressure 14 at port 79 to the inputs 32 and 42 of valves 30 and 40respectively.

An example of the manually operated valve 30 is shown in detail in FIG.3A. The operator 31 is a rocker mechanism held in its position down byspring 38. Upon movement in any 360 degree radial direction, it raisespushing valve element 35 off valve seat 33 against spring 37. Thisconnects the pressure source at input 32 to the outlet 36. In its stableposition shown, the valve element 35 sits on valve seat 33 closing offthe connection between supply at input 32 and the output 36. The output36 is connected via passage 75 to the volume 20. The structure shown is,for example, similar to the release valve DB10A available on the brakecontrol valve DB-60 available from New York Air Brake Corporation.

An example of the pneumatic valve 40 is shown in detail in FIGS. 3A and3B. The piston/operator 41 is a rocker mechanism held in its positiondown by spring 34. When the volume 20 is charged to the trip pressure,piston 41 raises pushing valve element 45 off valve seat 43 againstspring 47. This connects the pressure source at input 42 to the outlet46. In its stable position shown, the valve element 45 sits on valveseat 43 closing off the connection between supply at input 42 and theoutput 46. The output 46 is connected to the cylinder 10.

Although valve 30 shown in FIG. 3A is just an example of a manuallyoperated valve, other valves may be used, which automatically resets toa stable position upon removing the force applied manually. By using thespecific valve shown which is operable from multiple positions along thevehicle, only one valve 30 need be used for operation from both sides ofthe vehicle.

A third embodiment is shown in FIG. 4 including the manual valve 30connected at outlet 36 to the cylinder 10 and the volume 20. Thecylinder 10 is connected by cable 11 to the release mechanism of theparking hand brake 13. The manual valve 30 has the source of pressurefrom the reservoir 14 at input 32 and a second input 32′ connected toexhaust. An actuator 80 includes a piston 82 connected to by piston rod84 to the manual valve 30. The piston 82 divides the actuator 80 intotwo chambers including the volume 20 and volume 86. A spring 88, biasesthe piston 82 and the manual valve 30 to the deactivated position, notshown.

When the manual valve 30 is manually activated to the position shown inFIG. 4, its output 36 is disconnected from the exhaust at input 32′ andconnected to the source of pressure from reservoir 14 at inlet 32. Priorto activation of the manual valve 30, the cylinder 10 and both volumes20 and 86 of the actuator 80 are connected to exhaust by the manualvalve 30. After activation of manual vale 30, the piston 10 and thevolume 20 are charged and the cylinder 10 and piston 82 move to theposition shown in FIG. 4. The choke 22 and the pressure in volume 20prevent the volume 86 from being initially significantly charged. Thepressure in volume 20 initially holds the piston 82 and consequently themanual valve 30 in the activated position shown.

The air pressure in volume 86 increases with time as defined by at leastthe choke 22, since it is initially at a lower pressure than volume 20.As the air pressure in volume 86 in combination with the force of spring88 exceed the force produced by the pressure in chamber 20, the piston82 moves to the right in the figure and moves the manual valve 30towards its deactivated position. Once in the deactivated position,manual valve 30 connects the cylinder 10 and the volumes 20 and 86 toexhaust at input 32′. Due to the choke 22, the cylinder and the volume20 are depleted faster than volume 86. The spring 88 holds the manualvalve 30 in the deactivated position once all the volumes 86 and 20 aredepleted.

An example of the manual valve 30 and the actuator 80 of FIG. 4 isillustrated in FIGS. 5A, 5B, and 5C. The structure which is similar tothose of FIGS. 3 and 4 will have the same reference numerals. A manifold70 includes a body 72 with face plates 74 and 76. The manifold 70includes passages for interconnecting and in which is mounted the manualvalve 30, the volume 20, the first choke 22 and the actuator 80. Themanifold includes ports for the source of pressure 14 and the pneumaticcylinder 10.

The manual valve 30 and the actuator 80 are mounted in bore 71. Anexample of the manually operated valve 30 includes an operator 31 is arocker mechanism held in its position down by spring 38. Upon movementin any 360 degree radial direction, it raises from the position shown inFIG. 5A into engagement with the piston rod 84 of piston 82 of theactuator 80. Further upward movement and operation of the manual valveand actuator 80 are shown in FIGS. 5B and 5C.

The manual valve 30 and the actuator 80 are shown as an integral slidevalve structure. The piston 82 and the piston rod 84 form the slideelement of the slide valve and include gaskets 81, 83 and 85. The slideelement and the gaskets move relative to ports on the wall of the upperportion bore 71. The ports are connected to reservoir input 32, exhausts32, 32′ and output 36. Volume 20 is in bore 71 between the piston 82 andpiston rod 84. Volume 86 is on the other side of the piston 82 andincludes a spring 88. The choke 22 is a passage in the piston 82connecting the volumes 20 and 86.

A detent mechanism 90 is provided and includes a detent element 92 and aspring 94. The detent element 92 engages the side of piston rod 84 inFIGS. 5A and 5B and is below the piston rod 84 in FIG. 5C to retain itraised. Although the detent 90 defines a more binary or sharp end to theelongated time of activation of the release cylinder, the structure maybe used without the detent 90.

In the stable deactivated state of FIG. 5A, volumes 20 and 82 and output86 to the cylinder 10 are connected to exhaust inputs 32′. Reservoirinput 32 is sealed off by gaskets 83 and 84. During the initial motionof the manual operator 34, operator 31 engages the piston rod 84 andmoves the piston rod 84 and piston 82 up as shown in FIG. 5B. Thegaskets 81 and 85 respectively disconnect the volumes 20/output 36 and82 from exhaust inputs 32′. Gasket 83 terminates the connection of thesource of pressure input 32.

Further motion of the manual operator 34 and operator 31 move the pistonrod 84 and piston 82 up as shown in FIG. 5C. Gasket 83 uncovers thesource of pressure input 32 and connects it to the volume 22 and theoutput 64 to the cylinder. The gaskets 81 and 85 respectively continueto disconnect the volumes 20/output 36 and 82 from exhaust inputs 32′.The piston 82 and piston rod 84 are retained in this valved position bythe detent 90. The choke 22 slows the charging of the volume 82 comparedto the volume 20 and creates a pressure differential across piston 62.The pressure differential is sufficient to hold the piston 82 andconsequently the manual valve 30 in the activated position shown withoutthe detent 90.

The air pressure in volume 82 increases with time as defined by at leastthe choke 22, since it is initially at a lower pressure than volume 20.As the air pressure in volume 86 in combination with the force of spring88 exceed the force produced by the pressure in chamber 20 and asufficient force to overcome the detent 90, the piston 82 snaps down inthe figure to the deactivated position of FIG. 5A. Once in thedeactivated position, the cylinder 10 and the volumes 20 and 86 areconnected to exhaust at input 32′. The spring 88 holds the manual valvein the deactivated position once all the volumes 86 and 20 are depleted.

Although the present hand brake control system has been described andillustrated in detail, it is to be clearly understood that the same isby way of illustration and example only, and is not to be taken by wayof limitation. The scope of the present invention is to be limited onlyby the terms of the appended claims.

What is claimed:
 1. In a rail vehicle hand brake having a releaseactivated by a pneumatic cylinder, a control system comprising: a manualvalve having an output connected to a source of pressure at an inputwhen manually activated; a volume connected to the output of the manualvalve and charged by the source of pressure when the manual valve isactivated; and a choke connecting the volume to a source of lowerpressure when the volume is charged; whereby the volume and the chokeprolong the time the source of pressure is connected to the pneumaticcylinder after the manual valve is activated.
 2. The system according toclaim 1, including an actuator having a piston operatively connected tothe manual valve, and wherein the volume is in the actuator on a firstface of the piston for holding the piston and the manual valve actuatedfor the prolonged time.
 3. The system according to claim 2, wherein thechoke connects the volume to a volume on a second face of the pistonopposite the first face of the piston.
 4. The system according to claim2, wherein the choke is a passage in the piston.
 5. The system accordingto claim 1, wherein the volume is connected to a pneumatic cylinder. 6.The system according to claim 1, wherein the choke continuously connectsthe volume to the source of lower pressure.
 7. The system according toclaim 1, wherein the manual valve is a slide valve having a slide andthe piston is the slide of the slide valve.
 8. The system according toclaim 1, including a detent to hold the manual valve activated duringthe prolonged time.